In a medium pot of boiling water, blanch broccoli until firm tender, about 4 minutes. Use a slotted spoon to remove and plunge directly into an ice-water bath. Drain and dry. Toss with ⅛ teaspoon salt. Set aside.Meanwhile, fill a large plastic bag with potato starch. Add chicken pieces to starch mixture in bag, seal and shake to coat. Remove from bag and shake off any excess starch.

Sweet and sour sauce:In a bowl, whisk all ingredients together until well combined. Set asideOnce oil reaches 350 degrees. Cook golden brown, about 8-9 minutes. Use a slotted spoon to transfer to a paper-towel lined plate. Season with ⅛ teaspoon salt.

In a wok or large sauté pan over medium-high heat, stir-fry blanched broccoli and pineapple cubes in 2 tablespoons canola oil until caramelized, about 12 minutes. Add fried chicken and sweet and sour sauce, and cook until sauce boils and thickens, about 5 minutes. Everything should be evenly coated with sauce. Garnish with sliced scallions and season with remaining salt.